Antimicrobial activity of natural products from the skins of the semiarid living lizards Ameiva ameiva (Linnaeus, 1758) and Tropidurus hispidus (Spix, 1825)

The reptiles are the animal species most often used in traditional medicine. Tropidurus hispidus and ameiva ameiva are two species of lizards utilized as medicines in zootherapic practice in Brazilian semiarid region. In this work, we evaluated the antimicrobial activity of extracts of the skin of Ameiva ameiva (MEAA) and T. hispidus (METH). The samples were tested against standard and multiresistant strains of Escherichia coli, Staphylococus aureus and Pseudomonas aureuginosa, alone and in combination with aminoglycoside antibiotics. Alone, none of the samples showed significant inhibition of bacterial growth at clinically relevant concentrations. However, combinated with the antibiotics, MEAA potentiated the effect of amikacin and gentamicin, reducing their minimal inhibitory concentration (MIC) and the growth of E. coli and S. aureus. METH lowered the MIC of gentamicin against S. aureus. Chemical prospecting of the extracts revealed the presence of alkaloids in both, which can account for the modulatory action of the extracts, indicating a promising source of new drugs with antibiotic properties.

► Alkaloids were observed in the skin extract of semiarid lizards.
► The extracts are not clinically actives against pathogenic bacteria.
► The extracts potentiates the antibiotic activity of drugs.
► This point could explain its ethnopharmacological usage by traditional communities of the semiarid region of Brazil.